1. Field of the Invention
The present invention relates to a connecting device. for a piece of furniture, such as a sofa bed, more particularly to a connecting devrice for connecting a backrest frame and a seat frame at adjustable positions.
2. Description of the Related Art
FIG. 1 illustrates a conventional sofa bed 1 which includes left and right leg frames 11, front and rear horizontal bars 15 extending between the leg frames 11, and a seat frame 13 and a backrest frame 12 disposed on the horizontal bars 15 and between the leg frames 11. The sofa bed 1 incorporates a pair of connecting devices 2 for connecting the backrest frame 12 adjustably to the seat frame 13 such that the sofa bed 1 can serve as a bed or a sofa as desired. With further reference to FIG. 2, the connecting device 2 mainly includes a first connecting member 22 secured to the backrest frame 12, a second connecting member 23 pivoted to the first connecting member 22 and secured to the seat frame 13, a fixing plate 21 disposed below the first and second connecting members 22, 23 and attached securely to a cross-bar 111 of one of the leg frames 11, front and rear fixed support plates 24 interconnecting securely the fixing plate 21 and the second connecting member 23, a positioning piece 32 extending from the first connecting member 22 and formed with a plurality of positioning grooves 321, a holding pin 35 projecting from the second connecting member 23 for engaging one of the positioning grooves 321 so as to retain the backrest frame 12 at a folded position or an unfolded position relative to the seat frame 13, and a spring 331 for urging the positioning piece 32 against the holding pin 35. To adjust the position of the backrest frame 12, the backrest frame 12 is moved forwardly or rearwardly relative to the seat frame 13 for engaging the holding pin 35 with a selected one of the positioning grooves 321. However, since the second connecting member 23 is connected securely to the fixing plate 21, the seat frame 13 is kept stationary relative to the leg frames 11. As such, the sofa bed 1 still occupies a relatively large amount of space even when it is converted to a sofa, and is thus not satisfactory.
Therefore, an object of the present invention is to provide a connecting device for a sofa bed to enable the sofa bed to occupy less amount of space when converted to a sofa.
Another object of the present invention is to provide a sofa bed of the aforementioned type.
According to one aspect of the present invention, a connecting device is provided for use in a furniture frame having a support frame and first and second frame members disposed on the support frame. The connecting device includes a first connecting member, a second connecting member, a mounting plate and a pivotable linking plate unit. The first connecting member has a first end portion adapted to be fixed to the first frame member, and a second end portion opposite to the first end portion and formed with a plurality of ratchet teeth. The second connecting member has a front end portion adapted to be fixed to the second frame member, and a rear end portion pivoted to the second end portion of the first connecting member. The rear end portion is provided with a spring-loaded pawl unit. The mounting plate is disposed below the first and second connecting members, and is adapted to be fixes to the support frame. The linking plate unit has an upper end pivoted to the first end portion of the first connecting member, and a lower end pivoted to the mounting plate such that the first connecting member is movable forward and rearward relative to the mounting plate. The second connecting member is pivotable relative to the first connecting member in a first direction so as to enable the pawl unit to engage one of the ratchet teeth in order to retain the second connecting member at a certain angular position relative to the first connecting member. The second connecting member is pivotable relative to the first connecting member in a second direction opposite to the first direction so as to enable the pawl unit to slide past the ratchet teeth in order to dispose the front end portion of the second connecting member at a position coplanar with the first end portion of the first connecting member.
According to another aspect of the present invention, a furniture frame includes a support frame adapted to be supported on a ground surface, a first frame member disposed on the support frame, a second frame member disposed on the support frame and anteriorly of the first frame member, and a connecting device which includes first and second connecting members, a mounting plate and a pivotable linking plate unit. The first connecting member has a first end portion fixed to the first frame member, and a second end portion opposite to the first end portion and formed with a plurality of ratchet teeth. The second connecting member has a front end portion fixed to the second frame member, and a rear end portion pivoted to the second end portion of the first connecting member. The rear end portion is provided with a spring-loaded pawl unit. The mounting plate is disposed below the first and second connecting members and is fixed to the support frame. The linking plate unit has an upper end pivoted to the first end portion of the first connecting member, and a lower end pivoted to the mounting plate such that the first connecting member is movable forward and rearward relative to the mounting plate. The second frame member is pivotable relative to the first frame member in a first direction so as to enable the pawl unit to engage one of the ratchet teeth in order to retain the second frame member at a certain angular position relative to the first frame member. The second frame member is further pivotable relative to the first frame member in a second direction opposite to the first direction so as to enable the pawl unit to slide past the ratchet teeth in order to dispose the second frame member at a position coplanar with the first frame member.